The present invention relates to a method of producing a multi-nozzle head used in ink jet plotters.
Nozzles of ink jet plotter usually has a diameter of around 30.mu.. Various methods have been used for forming fine nozzle bores of the above-mentioned order by a direct processing of the raw material, such as photo-etching, mechanical processing with micro-drill, laser beam processing, electron beam processing and so forth.
These conventional processes, however, cannot provide satisfactorily high precision of diameter, circularity and cylindricalness of the fine nozzle bore, and cannot be suitably used particularly in the production of multi-nozzle heads in which uniform formation of a plurality of nozzle bores is an essential requisite.
For these reasons, indirect processing such as photoelectro forming have been adopted. Such indirect processing method, however, causes a melting of the material at the ends of the nozzle bore, resulting in a deteriorated cylindricalness of the bore. In addition, the process is impractically long and, hence, involves many factors which affect the diameter and circularity of the nozzle bore. Further, these indirect processing methods usually require a high initial cost.